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System Prompt Guide

The system prompt is the most important configuration for your agent. It defines who the agent is, what it does, and how it behaves.

Structure​

A good system prompt has three parts:

1. Role​

You are a support agent for Acme Corp. Your job is to help customers 
track orders, process returns, and answer product questions.

2. Behavior rules​

- Always greet the caller by name if you know it
- Keep responses concise — no more than 3 sentences at a time
- Do not discuss pricing unless the caller asks directly
- If you cannot resolve an issue, offer to escalate to a human agent

3. Scope limits​

Only answer questions related to Acme Corp products and orders. 
If asked about unrelated topics, politely redirect the conversation.

Voice-specific tips​

Since Vois agents operate over voice:

  • Write prompts as if the agent is speaking, not writing
  • Avoid bullet lists in responses — they don't translate to speech
  • Keep sentences short and natural
  • Use filler acknowledgments: "Got it", "Sure", "Let me check that for you"

Token limits​

Keep system prompts under 2,000 tokens for best performance. Very long prompts increase latency and can dilute the agent's focus.